The present invention relates to a computer system with a sound device providing a sound function and to a method of controlling the power supply of the sound device, and more particularly to a computer system capable of remarkably reducing the amount of electric power unnecessarily consumed by a sound device and to a method of controlling the power supply of the sound device.
In recent years, a variety of portable information devices that are easy to carry with and can operated from a battery have been developed. Most of the portable information devices of this type have a sound function for dealing with sound effects, music, speech, and the like.
The sound function is provided by a sound device (e.g., a sound controller) in the information device. The sound device is constituted by a dedicated logic circuitry composed of various circuits corresponding to the sound functions of a plurality of types, including WAVE sound and MIDI sound.
Recently, a new use of computers known as mobile computing has been finding its way in various fields. In mobile computing, the user loads only the necessary ones of the data items managed by a desk-top personal computer serving as, for example, a server into the user's easy-to-carry portable information device. Subsequently, the user does data processing work using the data in the portable information device at the user's destination or in the middle of moving to the destination. With the popularization of such mobile computing, the possible continuous running time of a computer operating from a secondary battery has begun to be considered important. In this connection, thorough power saving has been studied in the development of portable information devices.
The sound device, however, is constantly being powered as long as the power supply of the portable information device is in operation, regardless of whether the sound function is currently being used or not. This leads to a waste of electric power.
To sum up, the latest personal computers are provided with a sound device for providing a sound function. The sound device has the problem of wasting electric power, because electric power is constantly being supplied to the sound device as long as the power supply of the personal computer is in operation, regardless of whether the sound function is currently being used or not.